This invention relates, generally, to automatically stopping the operation of machinery, and more particularly, to cutting machines, such as wood chippers having one or more feed wheels for controlling the infeed of bulk wood products, one or more cutting blades which create and direct the produced wood chips toward a discharge chute, and an emergency safety device with a sensor array located in the infeed chute that directs control circuitry to stop the motive power directed to the feed wheels, the cutting blade, or both
Cutting machines such as wood chippers are used to reduce branches, trees, and other bulk wood products into small wood chips. A typical wood chipper often contains an infeed chute, a feed system for controlling the feed rate of wood products, a wood chipping mechanism, a drive system for the feed system and chipping mechanism, and a discharge chute. The infeed chute is typically a funnel-type conduit provided with a wide opening which tapers toward the feed system to converge the bulk wood products toward the chipping mechanism.
Through the action of the feed system, the bulk wood products are brought into contact with the chipping mechanism which grinds, flails, or cuts the wood products into small pieces and propels the small pieces into the discharge chute where they exit the wood chipper.
These types of wood chippers are, if operated incorrectly, dangerous devices. The chipping mechanism typically rotates at a high speed and produces high torques, which are necessary to chip the wood. The feed system located at the narrowest point of the infeed chute is a dangerous area which can catch a user's clothing or, more importantly, a user's limb if he improperly reaches into the infeed chute during operation of the chipper. If a user does get entangled in the feed system of known chippers, the user may not be able to reach a shutoff actuator located outside of the chute. Indeed, serious injuries continue to occur to operators of these devices.